When using eTASK.SmartReservation and all its extensions, rooms that require approval can be configured. These rooms are only actually booked after approval by the room manager. If the room manager makes the booking themselves, the booking does not require approval and is entered directly into the system. If the booking is not approved, it is not possible to hold a meeting in that room.
Note: If you book a room requiring approval via the eTASK.SmartReservation Outlook add-in, the meeting is saved in your calendar even if the booking has not yet been approved. If the room is neither approved nor rejected, this could lead to the mistaken assumption that the meeting room is available to you.